Manufacture of laminated glass



May 12, 1942. P. FINNEGAN MANUFACTURE OF LAMINATED GLASS Filed June 27, 1940 4 Sheets-Sheet 1 May 12, 1942, P. FINNEGAN 2,282,399-

MANUFACTURE OF LAMINATED GLASS File d June 27, 1940 k 4 Sheet s -Sheet 2' May 12, 1942; P. FINNEGAN MANUFACTURE OF .QAMINATED GLASS Fild June 27, 1940 4 Sheets-Shet :5

Patented May 12 1942 UNITED STATES. PATENT OFFICE MANUFACTURE OF LAMINATED GLASS Patrick "Finnegan, Jeannette, Pa., assignor to American Window Glass Company, Pittsburgh, Pa., a corporation of Pennsylvania Application June 2'7, 1940, Serial No. 342,746 4 Claims. (01. 49-815) The present invention relates generally to the manufacture of laminated glass, and more particularly-to the liquid or flow process of manufacturing laminated glass.

In the liquid or how process of manufacturing laminated glass, the glass sheets are first mechanically or chemically cleaned and are then "placed upon conveying apparatus for conveying the glass sheets past appropriate work stations. In one of the processes which is now being used commercially, the glass sheets are carried by the conveying mechanism into. and through an enclosure which is provided with brushing and exhausting mechanism for brushing the glass sheets to remove any particles of dust or lint that may coated sheets through an elongated drying chamber. In this chamber the films or coatings on the sheets are heated to suchan extent as to drive off a substantial portion of the solvent or other volatile constituents contained therein.

When the coated glass sheets are discharged from the exit end of the drying chamber, one of each pair of sheets is fiooded with a contacting agent and a sandwich formd of that sheet and another one. Thereafter, the sandwich is passed between rolls which squeeze out any excess contacting agent between the two films on the glass sheets and effect a preliminary contacting. Thereafter, the sandwiches are stacked vertically on a truck, and after the truck has been filled it is transferred to a pressure chamber where the sandwiches are subjected to sufiicient pressure distance, difliculty has been encountered in preventing the strengthening material which flows diownwardly past the leading, rear and side edges of the glass sheets from contaminating the conveying mechanism. As a consequence, it has heretofore been found necessary to place paper on the conveying mechanism beneath the glass sheets in order to catch the strengthening material flowing past the edges of the glass sheets. The strengthening material fiowing downwardly past the side edges of the glass sheets does not necessarily flow on these papers as it can be caught by appropriate pans or cups and recovered- It will be apparent, however, that the strengthening material fiowingpast the leading and rear edges of the glass sheets cannot be recovered in this way but has to be deposited on the paper positioned beneath the sheets. This strengthening material cannot be returned to the feeding mechanism and reused without expensive reconditioning thereof. As the quantity of this material which cannot be reused is very substantial and as materials capable of being used in processes of this character are quite expensive, this loss materially increases the manufacturing costs. Consequently, it is one of the objects of my invention to eliminate this loss and thereby materially reduce manufacturing costs.

The use of paper or any other simliar material beneath the glass sheets during the filming operation is quite objectionable. Inthe first place,

it materially adds to the cost of the process not only because of the cost of the paper itself but also because of the fact that it requires twice as many men to load the conveyor and place the paper thereon as is required where the paper is eliminated. In the second place, small particles'ofllint'or dirt come from the paper or- 'other material and are deposited on the glass sheets.

4 These small particles of dust or lint from the to effect a strong bond between the two coatings on the sheets.

In the carrying out of this liquid process as I practiced heretofore commercially, some diihculties have been encountered. A movable slat type of conveyor has heretofore been used for transporting the glass sheets past the filming machine, the glass sheets being \supported on raised blocks carried by the movable slats of the conveyor. As it is necessary to have the glass sheets spaced from each other at least a short paper are hard to detect except upon close examination of the glass sheets and frequently they are not removed'from the glass sheets by the exhausting mechanism positioned adjacent the filming feeder, and, if not, they form nuclei for bubbios and cause rejects. These rejects materially increase manufacturing costs. These objectionable features of the present liquid process are entirely eliminated by my invention.

In the liquid process, it is necesary that the film of strengthening material fed from the filming feeder downwardly onto the glass sheets be wider than the glass sheets. The viscosity of the strengthening material is quite low and if a film narrower than the glass sheet is formed and 2 Y p 2,282,399 flowed on the glass sheet; it not level on and completely'coverthe. top surface of the sheet; 'Thisisobjectionable because .it causes difiiculty in the further processing of the coated sheets and, 'imfact, results in a high percentage of rejects. If, on the'other hand, a solution of strengthening material having a higher viscosity is used, it willtend to fiow over the edges of the I glass sheets to such-an extent as to thin down the strengthening'material adjacent the edges of the sheet and this will cause difficulty and expense in the final compositing operation. For

these reasons, a solution of strengtheningmaterial having a relatively low viscosity is used tain a proper cut-oil, it is necessary to carefully control the operating conditions as well as the viscosity of the solution of strengthening mate- I rial. Even where careful control. is exercised, v some 'difiiculties are encountered and" aproper film is not formed on the glass-sheets-with the 25 result that rejects are occasioned.

By the present invention, I provide a method whereby a much better and more uniform eontrolcan be obtained" over the formation, of the film of' strengthening --material on the glass sheets, particularly along the edges thereof.

Where invention is utilized, I have found it possibleto maintain uniform edge conditions inthe film of strengtheningmaterial on the glass sheets and to modify as'desired the thickness and the general contour of the film of strengthening material adjacent'the edges of the glass sheets. In carrying out" my invention, I use a roller typeof" conveyingv mechanism for carrying the glass sheets In past the filming station."

Where this type of conveyor, as distinguished I from the movable slat type, is used it is possible.

to utilize a rotating roll positioned beneath the filming feederfand' this rotating" roll or other similar movable devicelwill receive the excess strengthening materialflowed over the edges. of the glass sheets and it can be passed to a collecting pan and returned to the; supply of strengthening material' and reusediQI have A frame and each shaft 1 is provided with a rubber vfound that where mechanism of this character is employed, the strengthening material losses i j are reduced toaininimum.

In addition, where a. rotating. ion or I other similar movable device-is utiliz 'ed forflreceiving' the excess materialfiowed downwardly past they vvother device .edges of the glass sheets, th nh I can be dt such a speed as to definitely control the cut-off along "the edges" of ,;the glass sheets in such a way as to providesubstantiallyuniform films along the edgesfof the glass sheets. I have also found that by appropriate control of the'relative speeds of the conveying'mech anism and the roll. or other similar movable mechanism, the character oi. the thickness .of the film along the edges can be controlled so that if it is desirable either a lighter or a heavier film can be formed along the edges than adjacent the central portion of the glass sheets. 7 'In some cases, this is highly desirable;

'Where my inventionis not utilized and the excess strengthening material dropping down- -wardly past the edges ofthexglas's sheets is strengthening material on the glass sheets 75 air- 2o drawings,

low, there is an insufiicient flow of the strengthening material over the glass sheets to iron out this hump around the edge of each glass sheet and, the adjacent depression. Where my. in-' 10, vention is used, I have found that this depression and the adjacent hump can be eliminated entirely satisfactorily so as to provide a film on each glass sheet which is substantially uniform in thickness fromone edge to the other edge. This is of substantial importance as it facilitates the compositing operation.

In the accompanying drawings, I have shown for purposes of illustration only a preferred apparatus for carrying out my invention. In the Fig." 1 is a side elevation of the apparatus spaced inwardly from the edges thereof a short distance. Between these depressions and the edges, th'ereis somewhat. of a hump of 'strengthening material. Due to the fact that the viscosity of the strengthening material is relatively 1 which may be employed in carrying out my in- 4 vention;

Fig. 2 is a central longitudinal section through portion of the apparatus removed; l

3 is a planview of the conveying table shown in-Fig. l; v Fig. 4 is an enlarged centrallongitudinal section through the filming apparatus;

- Fig. 5 is a section'taken. along th Fig; 6 is a section taken along the line VL-VI 5" 'l-is a view partly in sectionand partly in elevation showing the irolt on which the strengthening material is deposited;

/ Fig. 8 is a section taken along the line VIII- VIIIofFig.7;and'

4' Fig. 9 isa; section taken along the line IX -IX of. Fig. 7.

' 'AS shown in the drawings, the apparatus which" I employ-embodies a frame 2 comprising longitudinally extending angles 3 mounted on 'legs ,transversely extending channels 5 mount- 'sleeve- 9 which forms'the surface upon which 1 the glass sheets are carried. along the conveyor.

The sleeves 9 are preferablyof'rubber but they may be made of any other suitable material which provide sufficient frictional engagement with the. glass sheets to cause them to be carried at a relatively uniform rate of speed along'the conveying mechanism.

A plurality of conveying shafts it are alsomounted onthe frame-in bearings ll.

These shafts are not provided with rubber sleeves as are the shafts I, but each shaft has keyed to ita plurality of glass-supporting disks 12. These disks are preferably of some suitable pressed composition and are beveled to a point so that the bearing surfaces, between the disks and'the tire length of the shaft and the disks are keyed thereto by means'of wedgeshaped keys ll. The

purpose of having the keyways I! extend substantially throughout the lengths of the shafts is in order to permit the proper'positioning of the the apparatus shown in Fig.- 1 with thelower line vv with a worm l6 driven by a drive shaft l1. The

drive shaft H at its one end carries a sprocket wheel |6 driven by a chain l6 which, in turn,

, is driven by a motor 26 through speed reducing mechanism 2| and a sprocket wheel 22. Two of the shafts adjacent the discharge end of the conveying mechanism are not driven directly by the drive shaft H but are driven by means of a chain 23 which cooperates with sprocket wheels 24 carried on these shafts. This chain also extends over a sprocket 26v carried by .the last shaft l6 driven by the main "drive shaft |1.

By means of this arrangement, the glass sheets are carried at a relatively uniform rate of speed through the cleaning chamber 36, past the filming mechanism indicated generally by the reference character 3|, and through the enclosed chamber 32.

As each glass sheet passes into the cleaning chamber 36, a brush 33 loosens any dust or lint particles that may be on the surface thereofand these loosened particles are removed from the top surface of the glass sheet by an exhausting tube 34 connected to an exhauster (not shown).

After passing through the chamber 36, each glass sheet passes beneath the filming mechanism 3| which comprises a trough-shaped filming feeder 35 and a conduit 36 for supplying the strengthening material to the feeder. A valve 31 is provided in the'conduit 36 for controlling the rate of flow of the strengthening material to the feeder. The conduit 36 connects with a main header 36 having a control valve 36 therein. The main header 36 communicates directly with the supply of the strengthening material.

The fihning feeder 36 is formed of a bottom or rear plate 46, a front plate 4| and side plates 42. The front plate 4| is spaced slightly above the bottom or rear plate 46 so as to provide an orifice 43 through which the strengthening material P may flow. The bottom or rear plate 46 extends below the orifice 43 a substantial distance so that after the strengtheningmaterial passes through the orifice it will have an opportunity to spread or flow to some extent in order to form a film of substantially uniform thickness before passing over the bottom edge thereof. As shown in Fig. 4, the bottom edge 44 of the plate 46 is beveled rearwardly so that a sharp point is provided over which the strengthening material passes immediately before flowing onto the glass sheet S. The beveling of the bottom edge of this flow plate rearwardly is quite important in apparatus of this character as it prevents the material from freezing along the discharge .edge. An adjustable plate 46 is frame 46 is provided with downwardly extending legs 66 to which are welded angles 5| adapted to rest on the rods 52 which extend transversely of the conveying mechanism and are carried on the channels 6 by brackets 53.

As pointed out above, the width of the film of strengthening material P flowing over the bottom edge of the filming feeder is necessarily somewhat wider than the glass sheet being filmed. This excess strengthening material, as well as the excess'strehgthening material deposited by the feeder in the space between the rear edge of one light of glass and the leading edge of the adjacent light of glass, is deposited on a driven roll 66. This roll 66 may be of any suitable diameter and may be suitably located beneath the discharge end of the plate 46 of the feeder. The roll 66 is mounted in bearings 6| adjustably-supported 'on the channels 6. A bracket 62 is mounted on the one bearing 6| and a set screw 63 extends through the horizontally extending leg of this bracket and the bottom end thereof rests upon the adjacent channel 6. The other bearing 6| carries two brackets 64 having horizontally extending portions 65 through which are threaded set screws 66 which bear upon the adjacent channel 6. By appropriate adjustment of the set screws 63 and 66, .the roll 66 may be raised or lowered to suit particular operating conditions. Each bearing 6| is provided with a downwardly extending arm 61 and each arm has two slots 66 therein adapted to receive a screw 66 threaded in the adjacent bracket 6 for assisting in holding the roll in any adjusted position.

The shaft "l6 of the roll 66 extends beyond one of the bearings 6| and at its outer end carries a grooved wheel 1| which is keyed thereto. The roll 66 is driven through this grooved wheel by means of a belt 12, a motor 13, gear reducing and speed control mechanism 14 and a grooved wheel 15 which is driven by the gear reducer and speed controlling mechanism. In view of the fact that the roll 66 is vertically adjustable, provision is made for taking up any slack in the belt 12. This is accomplished by a roller 16 rotatably mounted on an arm 11 which is adjustably mounted on the adjacent channel 3 by a screw 16.

In operation, the excess strengthening material flows onto the roll 66 and is discharged therefrom into a trough 66 which is positioned below the roll and which extends transversely of the conveying mechanism. A spring-depressed -.doctor blade 6| is mounted adjacent the roll for mounted on the front plate 4| of the filming mathese adjusting screws bear 'on the transversely extending angles 46 of the frame 46; By means of these adjusting screws, the height of the feeder above the glass sheets can be adjusted. The

assisting in the removal of the excess strengthening material from the roll. The doctor blade 6| is pivotally mounted on brackets 62 depending from the bearings 6| for the roll 66. The pivots 63 of the doctor blade are located adjacent the lower end thereof and the springs 64, the lower ends of which are connected to fingers 66 mounted on the doctor blade and the upper ends of which are mounted on set screws 66, normally force the upper end of the doctor blade into contact with the roll 66. The set screws 66- are threaded through brackets 61- and may be adjusted vertically so that the springs may be placed under appropriate tension.

The trough 66 into which the excess material is deposited has a bottom outlet 66 through which the excess strengthening material is exhausted by means of an exhauster (not shown) and returned to the main supply of strengthening material.

Troughs 66 and 66 are provided beneath the conveying mechanism to catch any dirt, glass sheet passing thereover.

from the glass sheets or the conveying mechanism. The trough I also serves another It has a bottom outlet il connected to an ex--- hauster (not shown). The pur o e of this outlet and the exhauster is to withdraw from adjacent the apparatus some ofthe solvent contained in' the strengthening material which may have vaporized during and just after the filming opera tion. The solvent normally employed in the liquid process is, in general, heavier than air and,

consequentlmflittle diihculty is experienced in withdrawing this solvent from adjacent the'apparatus. It is desirable to withdraw this solvent as it is obnoxious'and some of it can be recovered.

It will be evident from what has been stated.

ables.' The distance between the top of-the out with regard. to the roll, 1. e.,' the location of ,the

' slot rela'tive to the center of'the' roll, and the height of the feeder abovethe glass can all be I varied somewhat and varying results achieved.

' Where the viscosity of the solution of strengthen .ing material is between'28' and 32 poises, it is V preferable to have the driven-cut-oif roll located.

about of an inch below the bottom of the glass Undersuch conditions, I the peripheral speed of thef-cut-ofi' roll should be I slightly greater'than the peripheral speed of the "conveying mechanism. It is also preferable un .de'r suchconditions to have the discharge edge of the feeder located approximately $4; of an'inch behind the center of the roll. The discharge edge of the feeder should also be located approxi- 'mately inch above the top'surface of the glass sheet passing thereunder; I

- When the peripheral speed of the-drivengcut-= oif roll'is increased so that it is appreciably great- --er than the peripheral speed of the conveying mechanism, the strengthening material along the edges r the glass sheet is thinned down to a is only slightly'greate'r than the speed of the conveying mechanism, the hump which is normally above that in order to achieve best results it is 1 desirable to properly correlate the diiferent'varisteps comprising moving the .45, l. ore that might be dropped seen that whendesirea an appreciable build-mi of strengthening material along the edgej 1 .eifectedand that this build-upeittends' weirdly of the edges of the glass sheet foria distance.v In normal operations, this buiidg fi is not desirablefas it is preferable to'have i e film I on each glass sheet substantially from one .edge to the other edge thereof; where operating conditions such as those mentioned above 10 as being the preferable operating ii'ditions are employed, substantially are j obtained and the cut-off of the strengthening material along the edge of the glass'sheetfis substantially uniform and there is no' fiowing of the film. over. the edgeso'f, the glass sheetsl'j In addition to the variables mentioned-above,

the diameter .of the cut-off rollfcan'be 'modiiied in order. to obtain varying results. "Where the ,diameteris appreciably reduced below that iiidlcated in the drawings, the driving speeds must be reduced .in order; to maintain an appropriate relationshlpbetween the peripheral speeds 'ofthe roll and the conveying mechanism.

vItwill be evident from what has been stated above that the present invention effects material savings in manufacturing costs and that it provides a much better control over the filming operation that can be obtained by prior artmethods.

Iolaimz; d; I

1. In themanufacture of. laminated glass, the H e sheet of glass in substantially horizontal position. past a filming station, flowing a film of a solution of strengthening material wider than the glasssheefidownwardly toward and onto the top surface or the sheet as it is carried past the filmihg station,

and, whilethe film is being flowed onto the glass 3 sheet, exerting a pullon the portion of the film passing downwardly past the edges of the glass the glass sheet.

sheet inxeess of that exerted on the by 2. In the manufacture of laminated ea the stepsv comprising moving a sheet of glass in,"s\1bstantiaiiy horizontal position "past a filming {station. .fiowin'g a film or a solution of strengthening material wider than the glass sheet down- .wardl'y toward and onto the top surface of the sheet as it is carried past the filming station,

7 l and, while the filmis being flowed onto the glass present at each side edge of the film on the glass sheet and the valley or depression which is nor- I .mally present immediately behind the .hump

Y .tial speed differential in operations as the sheet, controlling'the thickness of the iilmalong the sideedges' of thefltop surface of the glass sheet by exertinga'pull having a downward component on the portion of thepasslngdownwardly past theedges jof the glass sheet in excess strengthening material along the side edges of the glass'sheet is thinned down too greatly.

When the driven cut-oil. roll is driven at a peripheral speediof approximately one-fourth thatbf the peripheral speed of the conveying mechanism, I have found that the strengthening material along the side edges can be thickened to a very substantial extent. with this speed differential, I have found that the strengthening material along the edges can be built up ap-- proximately .009 inch on the'wet film and approximately .003 inch on the dry film. It will be appreciated that this is a substantial build-up along the edges as the thickness of the wet film. on each glass-sheet'is normally only .030 inch of thgt exerted on the film by the glass sheet.

3.'?;n ,the manufacture of laminated glass, the stepsco'mprising moving. a sheet or glass in substantially horizontal position pasta filming station, flowing a film of a solutiono'f strengthening material widerthan the: glass shoot down-- wardly toward and ontothe top surface or the sheet as it is carried pastthefilming station, and,-while the film is being flowed ontojtheglass sheets, exerting a; downward and forward pull on 'the portion of the film passing downwardly past the edges of the glass sheet sufilciently in excess of the downward and forward pull on the film exerted, by the. glass sheet to prevent the -material .frombuilding up, adjacent the edge of the sheet to a greater thickness than adjacent the centerthereof. I I

4.'In the manufacture of laminated glass, the

- steps comprising moving ash'eet of glass injsubstantially horizontalposition past a filmingsta-v 7 tion, flowing a film of a solution. of strengthenj' ing material wider than the glass sheet downwardly toward and onto the top surface of the sheet as it is carried past the filming station, collecting the excess material flowing past the edges of the glass sheet on a movable member, and moving the movable member at a speed greater than that of the glass sheet to pull downwardly and forwardly the portion of the film of strengthening material extending beyond the edges of the glass sheet to prevent the material from building up adjacent the edge of the sheet to a greater thickness than adjacent the center. g

PATRICK FINNEGAN. 

